Fourth-generation storage-ring-based X-ray synchrotron sources deliver photon beams with high brilliance and coherence. Although the transverse coherence of these beams is highly improved in the horizontal direction,
the overall coherent fraction is of the order of a few per cent for hard X-rays (\(>10\)  keV). Beamline optical elements such as pinholes and slits are then used to improve coherent fraction to values typically \(>80 \%\)  needed for applications exploiting coherence, such as X-ray photon correlation spectroscopy, coherent diffraction imaging, propagation-based phase-contrast imaging, and ptychography [1]}. The coherent beam interaction with the optical elements produce diffraction, thus modifying the beam characteristics and also affecting the beam focusing, as discussed here.
